8)HOW CAN WE SAVE ENERGY?

ENERGY EFFICIENCY

A energy-efficiency device requires less energy to perfom the same work.

We can apply strategies of energy efficiency in many areas of daily life. In this way, we can significantly reduce the amount of energy that we consume.

• Lighting:We can reduce the amount of electric light that we use by taking advantage of natural lighting. We can also replace traditional incandescent lightbulbs with energy-saving alternatives, such as LED bulbs.

• Domestic appliances: In recent years, domestic appliances have become much more efficient. New appliances have energy efficiency labels to indicate how much energy they consume. The most efficient devices consume the least energy.
• Air conditioning and heating: We use a lot of energy to keep our homes at a comfortable temperature, but there are ways we can be more efficient.
• Transport: The best way to consume less energy is to use public transport or to travel with other people when going long distances. For short distances, we can also walk or use bicycles to save energy. Electricals are also becoming more common. In addition to save energy, they cause less polution in urban areas.

RECYCLING

Our consumption of manufactures products generates waste and uses energy. We can reduce these negative effects by recycling as much as possible.

We can recycle products, we avoid the extraction and processing of more natural resources, In this way, we can save enormous amounts of energy.

In addition, recycling save water and reduces the emission of greenhouse gases into the atmosphere.

Recycling old batteries save energy, but it is also important because batteries contain toxic materials  that must be treated properly.

POSITIVE IMPACT

Energy efficiency has a beneficial effect on the environment.

When we consume less energy, it helps to reduce the greenhouse effect and climate change. Using less energy also reduces our explotation of natural resources.

Renewable energy sources are essential for solving our environmental problems. In the future, most of the electricity that we use will probably come from these cleaner, greener energy sources.At the moment, there are various projects to develop clean energy, such as nuclear fusion, which is the source of our Sun's energy. It is completely clean and it doesn't produce waste. It is also the most efficient energy that exists, because it uses small quantities of fuel to produce enormous amounts of energy.

7)ENVIRONMENTAL IMPACT

EFFECTS ON THE ENVIRONMENT
Extracting natural resources
Fossil fuels and radioactive elements, such as uranium, must be extracted from underground deposits. When those deposits are exhausted, we must find new ones to remplace them.
The extraction of mineral resources can also damage the environment. Large areas of forest have been destroyed to provide wood for fuel.
Transporting fuel
Most oils is transported over land through pipelines and by sea in large ships called oil tankers.
Natural gas is trasported over land through gas pipelines or by sea in tankers as liquid natural gas. These tankers are called LNG carries. Natural disasters and accidents can also affect gas pipelines and LNG carries.
Generating electricity
Hydroelectric power station require large amounts of water which must be stored behind dams in reservois. These reservois flood large areas of land and change the natural flow of the river. These changes have enormous effects in the ecosystem. In addition, if there is an accident and the dam breaks, the effects can be devastating for the environment and for the local people.


CLIMATE CHANGE
Most of our electricity come from power stations that use non-renewable energy sources. This situation is negative effects on the environment, and the most serious is climate change.

• When we burn fossil fuels, gases such as carbon oxide and methane are released into the air. These gases contribute to the greenhouse effect, which encreases the Earth's averages temperature.
• Already we can observe some of the effects of global warming, such as the melting of our polar ice caps and glaciers which leed to rising sea levels, and more extreme weather conditions in many places around the world.
• Power station that burns fossil fuels also release other polution into the air, such as sulphur oxide and nitrous oxide. These pollutants combine with water vapour in the air to produce acid rain, which damages our forest, lakes and rivers.
• These power station affect plants and animals life because they use refrigeration system that pump hot water into our rivers and oceans.

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ENERGY CONSUMPTION
The fossil fuels thah consumers use in their cars or home heating system also have an effect on the environment.
When we use electricity at home, we must also remember that most of that energy comes from non-renewable sources that cause a serious problems along the way. Electricity may seem like clean energy, but is generation and transportation can have serious effects on the environment.

7)ENVIRONMENTAL IMPACT

Power stations have an important impact on local ecosystems. For example, they require the construcion of new building and other infrastructure, such as power lines, roads and communication links. Power station also generate waste products that can affect the environment.
ENVIRONMENTAL IMPACT ASSSESSMENT
Any proposed new technological  project should include an environmental impact assessment. This should describe all of the ecological changes that the project could cause in the local area.There should also be an assessment of the economic and social repercussions of the project before any important decisions are made.

6)POWER STATIONS THAT USE RENEWABLE ENERGY SOURCES

BIOMASS POWER STATION
Biomass is any organic material that is produced by natural process.
There are many types of biomass which can be used to produce energy. Biomass is prepared through various physical and chemical natural process. For example, plant materials can be composted and fermented in tanks called digesters. These process convert biomass into fuel, such as charcoal, alcohol and biogas.
In a biomass power station, the fuel used to produce energy comes from biomass. The steam produced from burning the biomass move a turbine that is connected to a generator(alternator).
Biomass stations are efficient because they use waste materials that would normally end up in landfill sities.Altough biomass stations release CO2  into the atmosphere, they produce less pollution than conventional thermal power station.

MARINE POWER STATION

Marine power station use the movement of ocean water to generate electricity. They are very expensive and not very efficient. There are three general types of marine power stations:

-Tidal power station, which use the energy of tide.

-Wave power station, which use the energy of waves.

-Ocean thermal conversions stations, which use the difference in water temperature between the surface of the ocean and deeper areas to produce energy.

GEOTHERMAL POWER STATION

Geothermal power station use natural heat from the deepest underground layers of our planet. This heat comes from the Earth's surface as hot water, steam and hot gases.

Geothermal energy can be used in  two ways:

-It can be used directly to provide hot water for heating and industrial uses. In some places, this hot water is used for bathing health spas.

-It can be use indirectly to drive generators and produce electricity.

6)POWER STATIONS THAT USE RENEWABLE ENERGY SOURCES

HYDROELECTRIC POWER STATION
Hydroelectric power station use the energy of falling water to produce electricity. When water accumulates in a reservoid behind a high dam, it has a lot of potential energy which becomes kinetic energy when the water falls down to a lower level. This kinetic energy moves the blades of a turbines, which are usually located at the foot of the dam. The turbines are connected to the rotors of generators, which generate electricity. There are two main types of hydroelectric power station:
-In a conventional hydroelectric stations, the water flows from the reservoir to the turbines through a high-pressure conduit. Then it flows out, usually into a river.


-In a pumped-storage hydroelectric power station, the water flows from the turbines to a second reservoir. Then it is pumped back up to the higher reservoid and stored for later. These stations are often built in areas where there isn't enough rain or river water to keep the upper reservoir full, so the water must be reused.

SOLAR POWER STATIONS
Solar power stations use energy from sunlight to generate electricity. There are two main types of solar power station:Solar thermal and photovoltaic.
Solar thermal stations
Solar thermal sations can use sunlight in two ways:
-With solar collectors that absorb sunlight in order to produce heat.
-With mirrors called heliostats that reflect and concentrate sunlight in one place.

Photovoltaic stations
In photovoltaic stations, solar panel convert sunlight directly into electricity. Each panels contains many photovoltaic cells.
Small solar power installations can provide energy for homes and rural areas. Excess power can be stored in batteries or accumulators and used at night.

6)POWER STATIONS THAT USE RENEWABLE ENERGY SOURCES

Some power stations use clean,renewable energy sources to produce electricity. These alternatives help to reduce our dependence on non-renewable sources of energy, such as fossil fuels, which also cause environmental problems.
The renewable energy sources are wind power, hydroelectric power, solar power, marine power, geothermal power and biomass conversion. Although these energy source gives us less electricity that thermal power station, they have several advantages:
-They are greener that conventional power station because they produce less pollution.
-They use renewable energy, so they don't consume limited natural resource.
-They reduce our dependence on other countries that produce fossil fuels such as oil and natural gas. As a result, we don't need to important so much fuel.
-They are relatively cheap, in comparaison to other energy sources.
WIND FARMS
Wind farms use the kinetic energy of the wind to generate electricity. The wind turns the blades of a turbine, at the top of a tower. The blades are connected to gearbox which increases the rotational speed of the generator.
Wind farms are totally clean source of electricity. However, they must be installed in locations where there are strong, regular winds. Although wind power is a diffuse and intermittent source of energy, it is cheaper to produce than other enery source.
The output and efficiency of a wind farm depend on two factors;
-The location of the farm, which determines the speed and strength of the winds.
.The number of turbines that can be installed there.

5)ELECTRIC POWER STATIONS THAT USE NON-RENEWABLE ENERGY SOURCES

Most of electricity that we use comes from electric power station that use non-renawable energy sources. There are two types: Thermal power stations and nuclear power station.
THERMAL POWER STATION THAT USE FOSSIL FUELS
Thermal power stations use fossil fuels to produce thermal energy. Then the termal energy is converted to mechanical energy, in order to generate electricity.

Fossils fuels, are used to heat water in a boiler . Steam from the boiler turns a turbine, which is connected to the rotor of a generator. The generator produces electricity, which is transported by a network of high voltage power lines. After that, the steam goes to a condenser, where it cools and become liquid water again. Finally, the water is pumped back to the boiler.
Combined-cycle power station
In combined-cycle or cogeneration power stations, electricity is generated in two systems. The first system burns natural gases with compressed air. This produces superheated gases, which turn a turbine to generate electricity.
The second system use the hot gases from the first system and uses them to produce steam in a heat recovery boiler. Then the steam turns a turbine to generate more electricity. This make combines combine-cycle stations more efficient that single-cycle stations.
NUCLEAR POWER STATION
A nuclear power station is a thermal power station that uses a nuclear reactor to produce heat. The reactor uses radioactive material us fuel. The most commonly used materials are isotopes of uranium.

The main advantages of nuclear power stations are their productivity and profitability.They produce lost of electricity that can be sold at a profit.
The main disadvantages of nuclear power stations are the risks of nuclear accidents and the management and storage  of radioactive waste.

4)ELECTRICAL ENERGY

Electrical energy is a form of energy that is transported by an electrical current.
Electrical energy is the most commonly used energy in modern, industrialised socities. There are many technological objects around us that use electricity.
Electricity is very common for two reasons:
-It can be easily transformed into other types of energy, such as light and heat.
-It can be transported over long distances in ways that are cheap and efficient.

ELECTRICAL POWER STATION
A power station or generating station is a place where energy from natural resource is transformed into energy that we can consume. If the energy obtained is electricity, it is called an electric power station.
After the electricity has been generated, it can be transported to locations where enery is needed.
How electricity is generated
Electric power stations require source of energy, such as the mechanical energy of falling water. They use generators to transforms this energy into electricity. This generatos are called alternators.
An alternator usually has a stationary part, called a stator, and a moving part called a rotor. The rotor has an even number of coils that receive direct current.. The coils act like electromagnets and produce an electromagnetic field. A turbine turns the axis of the rotor, which generates an alternating electric current in each of the stator's coils, which coincide with one of every two of the rotor's coils.
The turbine-alternator system is used at all power stations except for photovoltaic stations, which use a different type of technology.

THE TRANSPORTATION AND DISTRIBUTION OF ELECTRICITY

In this video,  https://www.youtube.com/watch?v=wmAyLKEeLcM ,we can watch the transportation and distribution of electricity.